Microcontroller Studies The Blade

February 2, 2020 by Bryan Cockfield 8 Comments

Kendo, a Japanese martial art, is practiced with a special sword. It’s not a particularly sharp sword, though, since the “blade” is essentially a length of bamboo. For this reason, Kendo practitioners must rely on correct form and technique in order to make sure their practice is as effective as possible, and Cornell students [Iman] and [Weichen] have made a Kendo trainer that helps the swordsmen in their art.

The core of the project is a PIC32 microcontroller hooked up to a set of three piezoelectric sensors and a LSM9DS1 inertial module. The three piezoelectric sensors are attached to a helmet and the inertial module to the sword, and the sensors work together to determine both the location of the strike and whether or not it had enough strength to be considered a “good” strike (the rules of Kendo are beyond the scope of this article). The trainer can then calculate all of the information and provide feedback to the user on a small screen.

While martial-arts related builds seem to be relatively rare, we did find a similar project from back in 2011 called the Virtual Sensei which used a then-popular Kinect in order to track movements. This PIC32-based project, though, seems to be a little more thorough by including the strength of the strike in the information the computer uses, and is probably less expensive to boot!

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A Nano With An Otter’s Bite

February 1, 2020 by Jenny List 22 Comments

The would-be microcontroller experimenter is now faced with a bewildering array of choices when it comes to a tiny development board for their projects. Everything from descendants and clones of the original Arduino through to full-fat Linux powerhouses such as the Raspberry Pi Zero and similar boards can be had, and often for a reasonable price.

A new entrant has now joined the fray, the OtterPill is an STM32F072-based board with an Arduino-Nano-like pinout, and it comes from the bench of [Jana Marie]. With so many competitors you might ask yourself what it can offer, and it would be a valid point given that a Nano clone can be had for relative pennies. Aside from the Nano shield compatibility and extra power of the ARM Cortex M0 then, it’s an open source development board with USB-PD included from its USB-C socket, and with some elite BoM wizardry she’s managed to get the cost of its components to below three dollars. A USB-PD example firmware is available and a blank firmware is on its way. For now the board exists only in prototype form, but she’s putting together a production run if you would like one too. We saw an early development of it at eth0 back in the autumn, and given the progress since then we’re sure that we won’t have to wait for long.

Regular readers will recognise [Jana Marie]’s work, because otter-themed boards have made their way to these pages before. Our most recent ones were the USB-C replacement board bringing USB-PD to the TS-100 soldering iron, and a nifty little USB board for addressable LEDs.

Poking Around The Wide World Of Bluetooth

January 30, 2020 by Tom Nardi 8 Comments

Bluetooth is a technology with a very interesting history. When it first came around in the late 1990s, it promised to replace the mess of wires that was tucked behind every desk of the day. Unfortunately, the capabilities of early Bluetooth didn’t live up to the hype, and it never quite took off. It wasn’t until the rise of the smartphone more than a decade later that Bluetooth, now several versions more advanced, really started to make sense.

As [Larry Bank] explains in a recent blog post, that means there’s a whole lot to learn if you want to really understand Bluetooth hacking. For example, the Bluetooth versions that were used in the 1990s and 2000s are actually a completely different protocol from that which most modern devices are using. But the original protocol, now referred to as “Classic”, is still supported and in use.

That means to really get your head wrapped around working with Bluetooth, you need to learn about the different versions and all the tools and tricks associated with them. To that end, [Larry] does a great job of breaking down the primary versions of Bluetooth and the sort of tools you might find yourself using. That includes microcontrollers such as the ESP32 or Arduino Nano 33 BLE.

But the post isn’t just theory. [Larry] also goes over a few real-world projects of his that utilize Bluetooth, such as getting a portable printer working with his Arduino, or figuring out how to use those tiny mobile phone game controllers for his own purposes. Even if you don’t have these same devices, there’s a good chance that the methods used and lessons learned will apply to whatever Bluetooth gadgets you’ve got your eye on.

Readers may recall [Larry] from our previous coverage of his exploits, such as his efforts to increase the frame rate of the SSD1306 OLED display or his wireless bootloader for the SMART Response XE. Whenever we see his name pop up in the Tip Line, we know a fascinating hardware deep dive isn’t far behind.

Stylish Thermometer Is DIY Hardware Perfection

January 29, 2020 by Tom Nardi 14 Comments

Over the last few years, we’ve seen a steady improvement in the sort of custom hardware a dedicated individual can produce. With affordable desktop 3D printers and PCB fabrication services, the line between store bought and home built can get very blurry. This slick MQTT-connected thermometer created by [Martin Cerny] is a perfect example.

The case for the device, which [Martin] calls Temper, is printed in a stone-look PLA filament and has been carefully designed so that LEDs shining behind it illuminate perfect square “pixels” on the front. There’s a living hinge button on the left side, and on the right, an opening for the SHT30 temperature and humidity sensor. Some may say that the look of the sensor aperture could be improved with a printed grille, but there was likely a concern about reduced airflow.

Inside the case is a 13×7 array of SMD LEDs, a few 74HC595 shift registers, a TP4054 charging chip to keep the internal 250 mAh battery topped off via USB, and some passives to round out the party. The ESP-12E module that brings it all together and the battery are on the flip side of the PCB. At a press of the button, the display fires up for 5 seconds and Temper publishes temperature, humidity and battery percentage through MQTT. If you’re looking for more granular data, it can also be configured to publish regular updates at the cost of increased energy consumption.

The physical product is gorgeous on its own, but we’re happy to report that the firmware and documentation have been handled with a similar attention to detail. The project’s GitHub repo has a Wiki to help others build and configure their very own Temper, and the device’s web configuration portal is easily just as nice as anything you’d find in a piece of modern consumer electronics (if not moreso).

We’ve seen plenty of ESP8266-based environmental monitoring devices here at Hackaday, but we think this one really pushes the state-of-the-art forward. This is a device that wouldn’t be out of place on the shelf at a Big Box electronics retailer, and while [Martin] says he has no interest in building and selling them himself, we don’t doubt that folks out there will be spinning up their own Temper clones before too long.

Harmonicade Is A High-Scoring MIDI Controller

January 29, 2020 by Kristina Panos 12 Comments

When [KOOP Instruments] started learning the piano, he wasn’t prepared for the tedium of learning chords and their relationships on the standard keyboard layout. But instead of killing his desire to tickle the ivories, it inspired him to explore alternative layouts that are easier to play. He converted to Isomorphism, started building MIDI controllers, and hasn’t looked back.

The latest incantation is Harmonicade, a dual-decked number arranged Wicki-Hayden style. Both decks have 5½ octaves, are (electrically) identical, and run off a single Teensy 3.6. We admire [KOOP]’s use of DB25 connectors to wrangle the wiring between the decks and the Teensy — quite a neat solution. Almost as neat as his beautifully-commented code.

Although the button decks and control boxes are all printed and open source, they are designed to be easily made from acrylic or plywood instead. [KOOP] is going to keep iterating until he’s totally happy with the control locations and layout, and the ease of breakdown and reassembly. We’ve got a double shot of videos for you after the break — one of [KOOP] playing Harmonicade, and a longer one exploring and playing its precursor, the Melodicade.

Tired of conventional-looking MIDI controllers? We hear your bellows and offer this MIDI controller in a concertina.

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Supercon Keynote: Megan Wachs Breaks Down RISC-V

January 27, 2020 by Elliot Williams 17 Comments

The 2019 Hackaday Superconference kicked off with a marvelous, and marvelously geeky, keynote talk on the subject of RISC-V by Dr. Megan Wachs. She is VP of Engineering at SiFive, a company that makes RISC-V processors in silicon, but the talk is a much more general introduction to the RISC-V open instruction-set architecture (ISA) and why you’d care. The short answer to the latter is the same reason you care about any other open standard: it promotes interoperability, reusable toolchains, and will result in us all having access to better and faster CPUs.

The video is embedded below, and it’s absolutely worth a watch. Unfortunately, The video is missing the first few minutes, you can follow along through her slides (PDF) and read through our brief recap below of what fell down the video hole.

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ESP32 Serial Interface Modernizes Old Equipment

January 27, 2020 by Tom Nardi 25 Comments

There’s still plenty of useful hardware out there that uses an RS-232 interface, like the Behringer Ultradrive loudspeaker systems that [Lasse Lukkari] works with from time to time. Rather than ditch perfectly good gear because modern computers (to say nothing of phones or tablets) don’t have physical serial ports, he decided to come up with a WiFi adapter for these old devices that he calls SerialChiller.

Inside the SerialChiller is an ESP32, a MAX3232 line driver, a LM1117 linear regulator, and a few passives. The professionally manufactured PCB is housed inside of an enclosure that [Lasse] has repurposed from a cheap DB15 breakout adapter. The USB cable is used to power the board and for programming, though it can also be used to turn the SerialChiller into a USB-to-serial cable as well.

The hardware for this project is pretty straightforward, but what we really like is the direction he’s taken with the software. Rather than using the SerialChiller as a simple serial to WiFi bridge, [Lasse] is actually implementing a complete web-based interface directly on the microcontroller. In the video after the break he demonstrates his firmware for controlling the aforementioned Behringer Ultradrive, but that’s just one possible application for the project. Firmware could be spun up for all sorts of classic devices, breathing new life into hardware that might otherwise be in danger of heading to the landfill.

Of course, using the ESP family of chips as serial adapters is hardly anything new. In fact, that’s what they were designed for. But developing modern user interfaces for old hardware thanks to the power of the ESP32 has some fascinating potential.

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